Overview

The aim of this project is to enhance Vision with a RichText control that supports folding. The goal is to make this surface in the editor windows of EiffelStudio.

Introduction

While using an editor like the one provided by EiffelStudio the actual area in a text, in thsi case source code, that is actually being edited is restricted to a small part of the entire document. Therefor being able to remove text sequences from the display without changing the actual text sequence could increase productivity. One such approach is to use folding, which is a line-based technique that "folds" a block of lines into a single line that is then displayed in addition to a special symbol that marks the line as actually being a "pile" of lines, and which also serves as the interface to unfold the passage back into it's original state (and subsequent fold/unfold operations).

The Goal

The goal of this project was to implement folding support for the EiffelStudio editor in order to be able to fold semantic blocks of code such as entire features or loop blocks. The source text should however not be modified by this procedure in the sense that folding or unfolding a text should not change the AST. In addition folding should also not have any affects on any print output. A search for specific parts of code should also be able to enter folded text areas. It is also critical that folded areas are always displayed to the user correctly. Nested folding (e.g. a loop body in a feature, nested loops etc...) should also be possible.

ADT

(note: to be revised)

Types

FOLDING_WIDGET, TEXT_BLOCK, INTEGER, BOOLEAN,

Features

new -> FOLDING_WIDGET
definearea: FOLDING_WIDGET X HIGHLIGHTED_TEXT_BLOCK -> FOLDING_WIDGET
from: FOLDING_WIDGET -> INTEGER
to: FOLDING_WIDGET -> INTEGER
folded: FOLDING_WIDGET -> BOOLEAN
fold: FOLDING_WIDGET -> FOLDING_WIDGET
unfold: FOLDING_WIDGET -> FOLDING_WIDGET
content: FOLDING_WIDGET -> BLOCK
numberoflines: FOLDING_WIDGET -> INTEGER

Prerequisites

none

Axioms

for all w,v :: FOLDING_WIDGET, tb :: TEXT_BLOCK

from(definearea(w,tb)) = firstline(tb) to(definearea(w,tb) = lastline(tb) content(new) = NULL content(definearea(w,tb)) = tb numberoflines(new) = 0 numberoflines(definearea(w,tb)) = to(definearea(w,tb)) - from(definearea(w,tb)) folded(new) = false folded(fold(w)) = true

Classes

(note: to be revised)

EB_FOLDING_AREA Class holding all information about a single foldable area, for example

• starting line:INTEGER
• ending line:INTEGER
• folded:BOOLEAN
• ...

Testing

The following testcases have been propsed: - write a small application (source code to be provided by author) that includes multiple features, loops and nested loops to check the correct creation and display of folded areas (ncl. nested folds).

- print the source code of the application mentioned above with and without folding support. The output should be identical.

- compile and run both the source code with and without folding support. The applications behaviour should be identical.

- search for specific words and text segments within folded areas of the source. The search should find such segments.

TO DO

Part one :: generating the folding areas

This is the part where the data is gathered and put in to a datastructure to work on. Assigned to

• salmanasar
• grippus
• thomas
• sanakan

Done

• EB_FOLDING_AREAs are gathered from the class ast via click_tool.current_class.ast
• EB_FOLDING_AREAs are inserted stored in an avl-tree EB_FOLDING_AREA_TREE with doubly-linked leaves. features of EB_FOLDING_AREA_TREE include
  • first
  • last
  • item(k: key)

Part two :: graphical sidebar

A breakpoint-sidebar like widget to display our folding-handles in. Assigned to

• ledergec
• bru
• lord bubu

Part three :: text-manipulation

• Perro
• Panarium
• Exception

AST

To be familiar with ES' way of implementing the AST

done

• (half) ADT specified
• some specifications

Links

What is a folding editor?

How to implement an AST?

What's the Visitor Design-Pattern?

A paper about ADT's and text editors (download of the file with graphics)

Team

Everyone intrested in this project is welcome to join our mailinglist es-ui-fold@origo.ethz.ch

• sanakan (Project leader)
• Lord Bubu (Project leader)
• Bayt (Project Supervisor)
• Bru
• Exception
• Grippus
• Ledergec
• Panarium
• Perro
• salmanasar (aka. David, Quality Checking)